Engineering the Membrane–Electrode Interface at the Anode by Membranes with Porous Surface for Efficient Proton Exchange Membrane Water Electrolylsis

The membrane–electrode interface is essential in interfacial contact and catalyst utilization for proton exchange membrane water electrolysis (PEMWE). A facile method is proposed based on spraying a Nafion solution containing MgO microparticles to fabricate recast membranes with a porous surface. The effect of the MgO particle diameter on membrane morphology and electrochemical performance is investigated in detail. Results reveal that introducing a microengineered surface enhances the membrane–electrode interfacial area, improving interfacial contact and binding strength. The membrane prepared by the MgO particle with a medium size (1 μm in diameter) exhibits a relatively uniform porous architecture on the membrane surface and the largest membrane–electrode interface. Moreover, the microengineered interface enhances the electrochemical surface area and reduces the high-frequency resistance. As a result, the optimized catalyst-coated membrane (CCM) with the enlarged membrane–electrode interface produces a current density of 5.6 A cm–2 at 1.8 V, with a 37.5% improvement compared to the CCM with the planar membrane. Meanwhile, good durability lasting as long as 1000 h is also demonstrated for the optimized CCM.